fired up my 79 ford 460 to go for a drive today. carb is a 17080212 . it didn't what to run right ,wouldn't idle very good and had a slight bog when you mashed it to the floor. i don't drive it all that often about every couple of weeks. i built it a couple of years ago using cliffs parts (so i fiqured the parts had failed )ha ha . it acted like a vacuum leak . sure enough the black rubber caps that i purchased from napa had failed . all three of them ,i only use the timing advance port all the rest are plugged with the rubber caps, moral of the story if things are working fine look for something simple that causing the problem. if anybody knows where to get better rubber caps please let me know and i will purchase them.fwiw